Porous hollow α-Fe2O3@TiO2 core–shell nanospheres for superior lithium/sodium storage capability

Abstract

Porous hollow α-Fe₂O₃@TiO₂ core–shell nanospheres for use as anode materials in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) have been successfully fabricated by a simple template-assisted method, which has been rarely reported before. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N₂ adsorption–desorption isotherms reveal that the as-prepared α-Fe₂O₃@TiO₂ is composed of a hollow inner cavity and an outer shell with massive mesopores. This porous hollow structure is capable of buffering the large volume variation of α-Fe₂O₃ during cycling and preventing the electrode from pulverization and aggregation, as well as providing sufficiently large interstitial space within the crystallographic structure to host alkalis (Li and Na). As a consequence, this hybrid composite exhibits outstanding electrochemical properties, e.g., high specific capacity, excellent cyclability, satisfactory rate performance, and splendid initial coulombic efficiency for both LIBs and SIBs.